from chiplotle import *

def test_difference_01( ):
    '''Computes the difference of a list of ints.'''
    a = [1, 2, 3, 4]
    t = mathtools.difference(a)
    assert t == [1, 1, 1]
    assert isinstance(t, list)


def test_difference_02( ):
    '''Computes the difference of a CoordinateArray.'''
    a = CoordinateArray([(1, 2), (3, 4), (4, 4)])
    t = mathtools.difference(a)
    assert t == CoordinateArray([(2, 2), (1, 0)])
    assert isinstance(t, CoordinateArray)


def test_difference_03( ):
    '''The argument can be empty.'''
    t = mathtools.difference([ ])
    assert t == [ ]
    assert isinstance(t, list)


def test_difference_04( ):
    '''The argument can have one element.'''
    t = mathtools.difference([2])
    assert t == [ ]
    assert isinstance(t, list)
